Sample records for harvestman paranemastoma quadripunctatum

  1. Associative learning in a harvestman (Arachnida, Opiliones).

    dos Santos, Gilson Costa; Hogan, Jerry A; Willemart, Rodrigo Hirata


    Associative learning has been demonstrated in many species of invertebrates, but has not been studied in arachnids, except for some spiders and a whip-spider. Herein, we tested the ability of a Neotropical harvestman, Discocyrtus invalidus (Arachnida, Opiliones) to associate a shelter with a chemical stimulus. We used an arena with a white light at the top and two openings on the floor, one giving access to a dark shelter and the other one closed with a mesh. Filter paper with different chemicals (mate or green tea) surrounded both openings. A harvestman (n=37) was released in the arena and its behavior recorded. The procedure was repeated for 14 consecutive days with each individual. We found that harvestmen got faster at finding the refuge, became less exploratory and tended to move toward the open shelter as the days passed. We conclude that the animals learned to associate the chemical stimulus with the shelter.

  2. Penis morphology in a Burmese amber harvestman

    Dunlop, Jason A.; Selden, Paul A.; Giribet, Gonzalo


    A unique specimen of the fossil harvestman Halitherses grimaldii Giribet and Dunlop, 2005 (Arachnida: Opiliones) from the Cretaceous (ca. 99 Ma) Burmese amber of Myanmar reveals a fully extended penis. This is the first record of a male copulatory organ of this nature preserved in amber and is of special importance due to the age of the deposit. The penis has a slender, distally flattened truncus, a spatulate heart-shaped glans and a short distal stylus, twisted at the tip. In living harvestmen, the penis yields crucial characters for their systematics. Male genital morphology in H. grimaldii appears to be unique among the wider Dyspnoi clade to which this fossil belongs. The large eyes in the fossil differ markedly from other members of the subfamily Ortholasmatinae to which H. grimaldii was originally referred. Based on recent data, it has been argued that large eyes may be plesiomorphic for Palpatores (i.e. the suborders Eupnoi and Dyspnoi), potentially rendering this character plesiomorphic for the fossil too. Thus, the unique structure of the penis seen here, and the probable lack of diaphanous teeth, present in all other extant non-acropsopilionid Dyspnoi, suggest that H. grimaldii represents a new, extinct family of large-eyed dyspnoid harvestmen, Halithersidae fam. nov.; a higher taxon in amber diagnosed here on both somatic and genital characters.

  3. An enigmatic spiny harvestman from Baltic amber

    J. A. Dunlop


    Full Text Available A new harvestman (Arachnida: Opiliones from Baltic amber (Palaeogene: Eocene; ca. 44–49 Ma is described as Piankhi steineri n. gen., n. sp. This enigmatic fossil expresses long, slender pedipalps without a tarsal claw, which is characteristic for the suborder Dyspnoi. The chelicerae are notably enlarged and the dorsal body surface is formed from a carapace with a separate prosomatic tergite (metapeltidium, plus a large opisthosomal scute (or scutum parvum. However these characters, combined with the distinctly spiny limbs and further rows of spines across the fossil's opisthosoma, have no parallel among the modern dyspnoid harvestmen that we are aware of. The fossil resolves features reminiscent of modern members of the dyspnoid families Ceratolasmatidae, Nipponopsalididae, Ischyropsalididae and Sabaconidae, but does not show unequivocal apomorphies of any one particular family. We must entertain the possibility that this is an extinct body plan from the Eocene of north-central Europe, and we tentatively refer the fossil to a new genus in an unresolved position among the Ischyropsalidoidea (Dyspnoi. An amorphous triangular structure behind the anal region is assumed to be faecal matter, rather than part of the original anatomy. doi:10.1002/mmng.201200007

  4. The first fossil cyphophthalmid harvestman from Baltic amber

    Dunlop, Jason A.


    Full Text Available The first fossil cyphophthalmid harvestman (Opiliones: Cyphophthalmi from Palaeogene (Eocene Baltic amber is described. This is only the third fossil example of this basal harvestman lineage; the others being from the probably slightly younger Bitterfeld amber and the much older, early Cretaceous, Myanmar (Burmese amber. Although incomplete and lacking most of the appendages, the new Baltic amber fossil can be identified as a female. The somatic characters preserved, especially spiracle morphology and the coxo-genital region, allow it to be assigned with some confidence to the extant genus Siro Latreille, 1796 (Sironidae. This fossil is formally described here as Siro balticus sp. nov. It resembles modern North American Siro species more than modern European ones, and can be distinguished principally on its relatively large size and the outline form of the body.

  5. Iandumoema uai, a new genus and species of troglobitic harvestman from Brazil (Arachnida, Opiliones, Gonyleptidae

    Ricardo Pinto-da-Rocha


    Full Text Available A new genus and species of harvestman, landumoema uai, is described based on material from Gruta Olhos d'Água, Minas Gerais State, Brazil. Its troglomorphisms include depigmentation on body, legs and eyes. It is the third troglobitic species of harvestman recorded from Brazilian caves and the second in the family Gonyleptidae.

  6. Baltic amber harvestman types (Arachnida: Opiliones: Eupnoi and Dyspnoi

    J. A. Dunlop


    Full Text Available Baltic amber eupnoid and dyspnoid types (Arachnida: Opiliones in the Berendt collection are redescribed from their repository in the Museum für Naturkunde, Berlin. Type specimens of Caddo dentipalpis (Koch & Berendt, 1854, Dicranopalpus ramiger (Koch & Berendt, 1854, Nemastoma (? incertum Koch & Berendt, 1854, Mitostoma (? denticulatum (Koch & Berendt, 1854 and Histricostoma (? tuberculatum (Koch & Berendt, 1854 are all redescribed and the first photographs and camera lucida drawings of this material are presented. N.  (? incertum is removed from synonymy with M.  (? denticulatum. The status of the other Baltic amber harvestman types and their affinities are discussed. The type of Sabacon bachofeni Roewer, 1939 (= S. claviger (Menge, 1854 held in the Bavarian State collection, Munich is also redescribed here, but the repository of three other Roewer harvestman types and all of Menge’s types remains uncertain. The problematic Cheiromachus coriaceus Menge, 1854 is considered a nomen dubium, as is Phalangium succineum Presl, 1822, which may not even be a harvestman. Typenmaterial der Weberknecht-Gruppen Eupnoi und Dyspnoi (Arachnida: Opiliones vom Baltischen Bernstein aus der Berendt-Sammlung des Museums für Naturkunde Berlin wurde bearbeitet. Dabei wurde das Typusmaterial von Caddo dentipalpis (Koch & Berendt, 1854, Dicranopalpus ramiger (Koch & Berendt, 1854, Nemastoma (? incertum Koch & Berendt, 1854, Mitostoma (? denticulatum (Koch & Berendt, 1854 und Histricostoma (? tuberculatum (Koch & Berendt, 1854 revidiert und die ersten Fotografien und camera lucida-Zeichnungen dieses Materials hergestellt. N.  (? incertum wurde aus der Synonymie von M.  (? denticulatum herausgenommen. Der Status der anderen Weberknecht Typen aus dem Baltischen Bernstein und ihre Stellung werden diskutiert. Sabacon bachofeni Roewer, 1939 (= S. claviger (Menge, 1854 wird anhand des Holotypus aus der Bayerischen Staatssammlung M

  7. The distribution of the invasive harvestman Dicranopalpus ramosus in the Netherlands (Arachnida: Opiliones)

    Noordijk, J.; Wijnhoven, H.; Cuppen, J.G.M.


    Dicranopalpus ramous is one of the most characteristic harvestmen in our country. Because this species is quite easy to identify, many persons were able to contribute to the first distribution map ever presented for a harvestman species in the Netherlands. Remarkably, D. ramosus has succeeded to col

  8. Bioclimatic profile and potential distribution of the Mesopotamian harvestman Discocyrtus testudineus (Holmberg, 1876) (Opiliones, Gonyleptidae).

    Acosta, Luis E


    The geographic range of the Neotropical harvestman Discocyrtus testudineus (Holmberg, 1876) (Gonyleptidae) is addressed by determining the species' bioclimatic profile and modeling its potential distribution. Analysis was performed on a record set of 71 localities, including literature records and 34 new localities reported here. The bioclimatic profile was characterized through extreme, median and dispersion features of the values of 19 bioclimatic variables across the record set. Predictive models were built with the presence-only methods MAXENT and, secondarily, BIOCLIM. Discocyrtus testudineus is a typical Mesopotamian harvestman, spreading across a wide region along the middle and lower Paraná River in subtropical / temperate Argentina, and extending, more or less continuously, up to the central province of Córdoba. Apparently diverging records (Paso de los Libres, on the Uruguay River, and Quilmes, on the southern coast of Rio de la Plata) proved to be predictable, even if suppressed from the dataset. Comparisons of cumulative frequencies curves and dispersion features (box-plots) were made with Discocyrtus dilatatus Sørensen, 1884 and Gryne orensis (Sørensen, 1884), other Mesopotamian species for which bioclimatic data are available. The relative importance of the bioclimatic variables used for modeling was also estimated.

  9. Paecilaema batman, a new species of Brazilian troglophilous harvestman that exhibits a remarkable color patches variation (Opiliones: Cosmetidae

    Ricardo Pinto-da-Rocha


    Full Text Available A new species of harvestman, Paecilaema batman, from Brazilian limestone caves of the state of Goiás, is described, and a remarkable intraspecific color patch variation is discussed. Paecilaema batman sp. nov. differs from other species of the genus by the following combination of features: chelicera similar in both sexes; prosoma without color patches; typical color patches on area I; and area III with two high spines. The new species is considered troglophilous.

  10. Sperm morphology of the neotropical harvestman Iporangaia pustulosa (Arachnida: Opiliones): comparative morphology and functional aspects.

    Moya, J; Mancini, K; Machado, G; Dolder, H


    We describe herein the sperm morphology of the harvestman Iporangaia pustulosa. Adult males were dissected, the reproductive tract was schematized and the seminal vesicle was processed by light, transmission and scanning electron microscopy. The male reproductive tract is composed of a tubular testis, two deferent ducts, a seminal vesicle, a propulsive organ and a penis, similar to that observed in other Opiliones. The spermatozoa from the seminal vesicle are oval, aflagellate and immotile, presenting a nucleus surrounding an invagination of the cytoplasm, as well as a complex acrosome and projections on the cell surface. In the testis, spermatozoa are devoid of projections. In the seminal vesicle, they gradually acquire the projections with tufts adhering to it. Consequently, spermatozoa in various distinct stages of projection development can be found in the seminal vesicle. We believe that these projections (1) could help transport sperm along the male and perhaps female reproductive tracts; (2) are used to anchor the spermatozoa inside the female spermatheca in order to avoid mechanical displacement by the genitalia of other males and (3) may play a role in oocyte recognition. We propose that the evolution of aflagellarity in Opiliones is related to the unique morphology of the female reproductive tract. Since eggs are fertilized on the tip of the ovipositor just prior to being laid, there is no advantage favoring sperm mobility. Additionally, female sperm receptacles are small and males that produced small spermatozoa would have a higher chance of fertilizing more eggs.

  11. Sexually dimorphic legs in a neotropical harvestman (Arachnida, Opiliones): ornament or weapon?

    Willemart, Rodrigo H; Osses, Francini; Chelini, Marie Claire; Macías-Ordóñez, Rogelio; Machado, Glauco


    The evolution of sexually dimorphic traits has been the focus of much theoretical work, but empirical approaches to this topic have not been equally prolific. Males of the neotropical family Gonyleptidae usually present a strong fourth pair of legs armed with spines, but their functional significance is unknown. We investigated the putative functions of the leg armature in the harvestman Neosadocus maximus. Being a non-visual species, the spines on male legs can only be perceived by females through physical contact. Thus, we could expect females to touch the armature on the legs of their mates if they were to evaluate it. However, we found no support for this hypothesis. We did show that (1) leg armature is used as a weapon in contests between males and (2) spines and associated sensilla are sexually dimorphic structures involved in "nipping behavior", during which a winner emerged in most fights. Finally, we demonstrate that five body structures directly involved in male-male fights show positive allometry in males, presenting slopes higher than 1, whereas the same structures show either no or negative allometry in the case of females. In conclusion, leg armature in male harvestmen is clearly used as a device in intrasexual contests.

  12. Deep genetic divergences in Aoraki denticulata (Arachnida, Opiliones, Cyphophthalmi): a widespread 'mite harvestman' defies DNA taxonomy.

    Boyer, Sarah L; Baker, Jessica M; Giribet, Gonzalo


    Aoraki denticulata (Arachnida, Opiliones, Cyphophthalmi, Pettalidae), a widespread 'mite harvestman' endemic to the South Island of New Zealand, is found in leaf littler habitats throughout Nelson and Marlborough, and as far south as Arthur's Pass. We investigated the phylogeography and demographic history of A. denticulata in the first genetic population-level study within Opiliones. A total of 119 individuals from 17 localities were sequenced for 785 bp of the gene cytochrome c oxidase subunit I; 102 of these individuals were from the Aoraki subspecies A. denticulata denticulata and the remaining 17 were from the subspecies A. denticulata major. An extraordinarily high degree of genetic diversity was discovered in A. denticulata denticulata, with average uncorrected p-distances between populations as high as 19.2%. AMOVA, average numbers of pairwise differences, and pairwise F(ST) values demonstrated a significant amount of genetic diversity both within and between populations of this subspecies. Phylogenetic analysis of the data set revealed many well-supported groups within A. denticulata denticulata, generally corresponding to clusters of specimens from single populations with short internal branches, but separated by long branches from individuals from other populations. No haplotypes were shared between populations of the widespread small subspecies, A. denticulata denticulata. These results indicate a subspecies within which very little genetic exchange occurs between populations, a result consistent with the idea that Cyphophthalmi are poor dispersers. The highly structured populations and deep genetic divergences observed in A. denticulata denticulata may indicate the presence of cryptic species. However, we find a highly conserved morphology across sampling localities and large genetic divergences within populations from certain localities, equivalent to those typically found between populations from different localities. Past geological events may have

  13. First Harvestman Record for the Juan Fernández Archipelago, Chile, with Morphological Notes on Acropsopilio chilensis (Opiliones: Caddidae: Acroposopilioninae).

    Pérez-González, Abel; Ramírez, Martín J; Soto, Eduardo M; Pizarro-Araya, Jaime


    Acropsopilio chilensis Silvestri, 1904 (Eupnoi: Caddidae: Acropsopilioninae), is recorded for Robinson Crusoe Island, Chile. This is the first harvestman species recorded for the Juan Fernández Archipelago and also the first extra-continental record for this species. During the comparison with continental co-specific specimens, some previously unknown, remarkable morphological characteristics were discovered, among them: the absence of ovipositor seminal receptacles and tracheal system, small and probably imperforate spiracles and the presence of a subdistal spiny structure, maybe a stylus, in the major branch of the penis. 

  14. Longipin: An Amyloid Antimicrobial Peptide from the Harvestman Acutisoma longipes (Arachnida: Opiliones) with Preferential Affinity for Anionic Vesicles

    Batista, Isabel de Fátima Correia; de Melo, Robson Lopes; Riske, Karin A.; Daffre, Sirlei; Montich, Guillermo; da Silva Junior, Pedro Ismael


    In contrast to vertebrate immune systems, invertebrates lack an adaptive response and rely solely on innate immunity in which antimicrobial peptides (AMPs) play an essential role. Most of them are membrane active molecules that are typically unstructured in solution and adopt secondary/tertiary structures upon binding to phospholipid bilayers. This work presents the first characterization of a constitutive AMP from the hemolymph of an Opiliones order animal: the harvestman Acutisoma longipes. This peptide was named longipin. It presents 18 aminoacid residues (SGYLPGKEYVYKYKGKVF) and a positive net charge at neutral pH. No similarity with other AMPs was observed. However, high sequence similarity with heme-lipoproteins from ticks suggested that longipin might be a protein fragment. The synthetic peptide showed enhanced antifungal activity against Candida guilliermondii and C. tropicalis yeasts (MIC: 3.8–7.5 μM) and did not interfered with VERO cells line viability at all concentrations tested (200–0.1 μM). This selectivity against microbial cells is related to the highest affinity of longipin for anionic charged vesicles (POPG:POPC) compared to zwitterionic ones (POPC), once microbial plasma membrane are generally more negatively charged compared to mammalian cells membrane. Dye leakage from carboxyfluorescein-loaded POPG:POPC vesicles suggested that longipin is a membrane active antimicrobial peptide and FT-IR spectroscopy showed that the peptide chain is mainly unstructured in solution or in the presence of POPC vesicles. However, upon binding to POPG:POPC vesicles, the FT-IR spectrum showed bands related to β-sheet and amyloid-like fibril conformations in agreement with thioflavin-T binding assays, indicating that longipin is an amyloid antimicrobial peptide. PMID:27997568

  15. A new highly specialized cave harvestman from Brazil and the first blind species of the genus: Iandumoema smeagol sp. n. (Arachnida, Opiliones, Gonyleptidae)

    Pinto-da-Rocha, Ricardo; da Fonseca-Ferreira, Rafael; Bichuette, Maria Elina


    Abstract A new species of troglobitic harvestman, Iandumoema smeagol sp. n., is described from Toca do Geraldo, Monjolos municipality, Minas Gerais state, Brazil. Iandumoema smeagol sp. n. is distinguished from the other two species of the genus by four exclusive characteristics – dorsal scutum areas with conspicuous tubercles, enlarged retrolateral spiniform tubercle on the distal third of femur IV, eyes absent and the penial ventral process slender and of approximately the same length of the stylus. The species is the most highly modified in the genus and its distribution is restricted only to caves in that particular area of Minas Gerais state. The type locality is not inside a legally protected area, and there are anthropogenic impacts in its surroundings. Therefore, Iandumoema smeagol sp. n. is vulnerable and it must be considered in future conservation projects. PMID:26798238

  16. More on the Mesopotamian-Yungas disjunction in subtropical and temperate Argentina: Bioclimatic distribution models of the harvestman Discocyrtus dilatatus (Opiliones: Gonyleptidae

    Julia Vergara


    Full Text Available ABSTRACT In this paper, the potential distribution of the Mesopotamian harvestman Discocyrtus dilatatus Sørensen, 1884 is modeled, and the species' bioclimatic profile is described. Models were built with the presence-only methods Maxent and Bioclim, using 85 unique records (of which 49 are new and 11 non-correlated bioclimatic variables as predictors. Both Maxent and Bioclim supported the Mesopotamian-Yungas disjunct pattern observed in D. dilatatus, and confirmed the hypothesis that the sub-xeric Dry Chaco is an effective barrier for the two portions of the range. Similarly to results of previous studies on other Mesopotamian harvestmen, temperature variables proved more relevant than precipitation variables in the final models. In the combined overall score obtained with Maxent, bc4-temperature seasonality ranked as the most relevant, and only one precipitation variable (bc18-precipitation of warmest quarter, in second place ranked among the top five. In the Most Limiting Factor analysis, which identifies the relevant variables in a local scale, temperature variables were again more determining than precipitation variables in most of the range. One single variable, bc5-maximal temperature of warmest month, proved critical near the boundaries of the modeled range and the Dry Chaco, suggesting that extremely high temperatures (and not the supposed aridity are responsible for the 450 km distribution gap.

  17. A taxonomic catalogue of the Dyspnoi Hansen and Sørensen, 1904 (Arachnida: Opiliones).

    Schönhofer, Axel L


    . (=Paranemastoma quadripunctatum (Perty, 1833)), Crosbycus graecus Giltay, 1932 syn. n. (=Paranemastoma simplex (Giltay, 1932)), Nemastoma bimaculosum Roewer 1951 syn. n. (=Paranemastoma titaniacum (Roewer, 1914)), Trogulocratus tunetanus Roewer, 1950 syn. n. (=Calathocratus africanus (Lucas, 1849)), Trogulus albicerus Sø-rensen, 1873 syn. n. (=Calathocratus sinuosus (Sørensen, 1873)), Metopoctea exarata Simon, 1879a syn. n. (=Trogulus aquaticus Simon, 1879a), Trogulus galasensis Avram, 1971 syn. n. (=Trogulus nepaeformis (Scopoli, 1763)) and Trogulus roeweri Avram, 1971 syn. n. (=Trogulus nepaeformis (Scopoli, 1763)). Paranemastoma werneri (Kulczyński, 1903) is elevated from subspecies to species. Ischyropsalis luteipes Simon, 1872b is proposed as nomen protectum, taking precedence over Lhermia spinipes Lucas 1866 nomen oblitum. The same accounts for Anelasmocephalus cambridgei (Westwood, 1874) nomen protectum, taking precedence over Trogulus violaceus Gervais, 1844 nomen oblitum, Trogulus closanicus Avram, 1971 nomen protectum over Trogulus asperatus C.L. Koch, 1839a nomen oblitum, as well as Trogu-lus martensi Chemini, 1983 nomen protectum over Trogulus tuberculatus Canestrini, 1874 nomen oblitum. New combinations, all from Nemastoma, are Histricostoma anatolicum (Roewer, 1962), Mediostoma globuliferum (L. Koch, 1867), Nemastomella hankiewiczii (Kulczyński, 1909), Nemastomella maarebense (Simon, 1913), Nemastomella monchiquense (Kraus, 1961) and Paranemastoma simplex (Giltay, 1932); from Mitostoma: Nemastomella armatissima (Roewer, 1962). Revived combinations are Nemastomella cristinae (Rambla, 1969) (from Nemastoma) and Nemastomella sexmucronatum (Simon, 1911) (from Nemastoma). The following Nemastoma are transferred to Paranemastoma but suggested as nomina dubia: aeginum (Roewer, 1951), amuelleri (Roewer, 1951), bolei (Hadži, 1973a), caporiaccoi (Roewer, 1951), carneluttii (Hadži, 1973a), ferkeri (Roewer, 1951), gigas montenegrinum (Nosek, 1904), gostivarense (Had

  18. Sinostoma yunnanicum, the first nemastomatine harvestman in China (Arachnida: Opiliones: Nemastomatidae).

    Martens, Jochen


    The easternmost Nemastomatinae species, Sinostoma yunnanicum n. gen., n. sp., from northern Yunnan, China is described. It extends the geographic distribution of Nemastomatinae by roughly 3000 km southeastwards. Within Nemastomatinae Sinostoma displays plesiomorphic characters, including the long, basic bulb of the truncus shaft and the extremely short glans of penis, armed with short robust spines. Sinostoma may represent a relict line in the early evolution of nemastomatine harvestmen.

  19. First experimental evidence that a harvestman (Arachnida: Opiliones detects odors of non-rotten dead prey by olfaction

    Thaiany Miranda Costa


    Full Text Available Harvestmen feed on live, dead and fresh, or decomposing animals, fungi, and plant matter, being very dependent on chemoreception to find food. Herein we performed an experiment to test if individuals of Discocyrtus pectinifemur Mello-Leitão, 1937 (Gonyleptidae (n = 23 behave differently when in contact with olfactory cues from different sources (rotten prey, non-rotten prey and a control. Using dead crickets in a box covered with a mesh, and recording the time the harvestmen spent in the vicinities of the box, we show that D. pectinifemur detects non-rotten prey and stays longer on it than on the other two treatments. Our results contrast with a previous study on another species, showing that we should not generalize results obtained for one species. Our data also suggest that olfactory receptors occur on the legs of these harvestmen and that D. pectinifemur might choose dietary items based on olfaction.

  20. Mitochondrial rRNA secondary structures and genome arrangements distinguish chelicerates: comparisons with a harvestman (Arachnida: Opiliones: Phalangium opilio).

    Masta, Susan E


    Arachnids are a highly diverse group of arthropods, and many of the mitochondrial genomes that have been sequenced from arachnids possess unusual features in their inferred gene structures and genome organization. The first complete sequence of a mitochondrial genome from the arachnid order Opiliones (harvestmen) is presented here. Secondary structures of the two mitochondrial ribosomal subunits of Phalangium opilio are inferred and compared to mitochondrial rRNA structures of a hexapod and a chelicerate. The large subunit rRNA of P. opilio is found to have more helices conserved than in other arthropods, while the small subunit rRNA shows a complexity similar to that of other arthropods. These comparisons suggest that a reduction in rRNA complexity occurred in Pancrustacea after the divergence of Pancrustacea and Chelicerata from a common ancestor. The gene arrangement of the mitochondrial genome of P. opilio is compared with the gene order of taxa from all seven other orders of arachnids for which representative mitochondrial genomes have been sequenced. Taxa from five of these seven orders possess gene arrangements identical to that of Limulus polyphemus, and P. opilio is found to have a similar arrangement. However, in P. opilio, some genes near the putative control region are rearranged, with the suite of genes encoding tRNA(Gln), the control region, and tRNA(Ile) located downstream of the two ribosomal RNA genes, and upstream of where they are typically located in chelicerates. The genome encodes only 21 of the typical 22 mitochondrial tRNA genes and lacks the gene for tRNA(Leu(CUN)). The protein-coding genes in the mitochondrial genome of P. opilio show a significantly decreased use of codons recognized by tRNA(Leu(CUN)), likely due to selection to utilize the more specific tRNA(Leu(UUR)) anticodon. The gene arrangement and lack of a tRNA(Leu(CUN)) gene in P. opilio is most parsimoniously explained by the occurrence of at least two translocation events, one of which probably destroyed the function of the tRNA(Leu(CUN)) gene. Phylogenetic relationships among the major orders of arachnids are inferred, using all 13 mt protein-coding genes, and gene rearrangements are mapped onto the phylogeny. The phylogenetic analyses are unable to resolve the placement of P. opilio but are generally consistent with an early divergence of members of the Dromopoda (harvestmen, scorpions, and solifuges) from the Micruran arachnids (spiders, whip spiders, vinegaroons, ricinuleids, and mites). However, unlike some morphologically based phylogenetic analyses, the existence of a clade of Dromopoda is not supported. While data on genome arrangement and gene loss do not provide further information to help resolve relationships among the arachnid orders, they distinguish some groups of arachnids, distinguish chelicerates from other arthropods, and further clarify the ancestral gene order of this diverse group of arthropods.

  1. Evolutionary and biogeographical history of an ancient and global group of arachnids (Arachnida: Opiliones: Cyphophthalmi) with a new taxonomic arrangement

    Giribet, Gonzalo; Sharma, Prashant P.; Benavides, Ligia R.


    We investigate the phylogeny, biogeography, time of origin and diversification, ancestral area reconstruction and large-scale distributional patterns of an ancient group of arachnids, the harvestman suborder Cyphophthalmi. Analysis of molecular and morphological data allow us to propose a new cla...

  2. Endemic harvestmen and spiders of Austria (Arachnida: Opiliones, Araneae

    Komposch, Christian


    Full Text Available A comprehensive overview of plant, fungus and animal species of Austria revealed a total of 748 endemic and subendemic species, including, 11 harvestman and 46 spider species. Altogether two endemic harvestmen (Nemastoma bidentatum relictum, Nemastoma schuelleri and 8 endemic spiders (Abacoproeces molestus, Collinsia (caliginosa nemenziana, Mughiphantes severus, Mughiphantes styriacus, Pelecopsis alpica, Scotophaeus nanus, Troglohyphantes novicordis, Troglohyphantes tauriscus, beside 9 subendemic harvestman and 38 subendemic spider species have been recorded from Austria. Hot-spots of endemism in the Eastern Alps are the north-eastern (Ennstaler Alps and southern Calcareous Alps (Karawanken, Karnische Alps and the Central Alps (Hohe Tauern, Gurktaler Alps, Ötztaler and Stubaier Alps. Most of the endemic arachnid species occur from the nival down to the montane zone. Important habitats are rocky areas, caves and woodlands. High absolute numbers and percentages of endemics can be found within the harvestman families Cladonychiidae, Ischyropsalididae and Nemastomatidae and in the spider genera Lepthyphantes s. l. and Troglohyphantes. The conservation status of these highly endangered taxa – 85 % of the spider species and 100 % of the harvestman taxa are endangered in Austria – is poor.

  3. Spiders and harvestmen on tree trunks obtained by three sampling methods

    Machač, Ondřej


    Full Text Available We studied spiders and harvestmen on tree trunks using three sampling methods. In 2013, spider and harvestman research was conducted on the trunks of selected species of deciduous trees (linden, oak, maple in the town of Přerov and a surrounding floodplain forest near the Bečva River in the Czech Republic. Three methods were used to collect arachnids (pitfall traps with a conservation fluid, sticky traps and cardboard pocket traps. Overall, 1862 spiders and 864 harvestmen were trapped, represented by 56 spider species belonging to 15 families and seven harvestman species belonging to one family. The most effective method for collecting spider specimens was a modified pitfall trap method, and in autumn (September to October a cardboard band method. The results suggest a high number of spiders overwintering on the tree bark. The highest species diversity of spiders was found in pitfall traps, evaluated as the most effective method for collecting harvestmen too.

  4. A new species of Metagovea Rosas Costa, 1950 from Napo Province, Ecuador (Opiliones, Cyphophthalmi, Neogoveidae).

    Giupponi, Alessandro P L; Kury, Adriano Brilhante


    As a result of an expedition to Ecuador in 2014, a new species of mite harvestman was discovered. This new species belonging to the genus Metagovea Rosas Costa, 1950 - Metagovealigiae sp. n. - is described, based on male and female specimens from Napo Province, Ecuador. This is the fourth species described for the genus and the second from Ecuador. A simple terminology is proposed for the microtrichiae of the spermatopositor and genital characters in the family are discussed. The genus Brasiliogovea Martens, 1969 is consistently misspelled in the literature as Brasilogovea. The description of Metagovealigiae offered opportunity to discuss some aspects of systematics of the family.

  5. Das Höhlenlangbein Amilenus aurantiacus (Opiliones: Phalangiidae ist Höhlentier des Jahres 2016 in Deutschland

    Zaenker, Stefan


    Full Text Available With the nomination of the ‘Cave Animal of the Year’ the Society of German Cave and Karst Explorers calls public and authorities’ attention to the understudied biodiversity of subterranean ecosystems. Here the Cave Animal of the Year 2016, Amilenus aurantiacus (Simon, 1881, is presented. It is the first time that a harvestman has been chosen. Ist ecology, habitat and morphology are described. New records from Hesse, Bavaria, Baden-Württemberg and North Rhine-Westphalia are listed and discussed.

  6. Egg Production Constrains Chemical Defenses in a Neotropical Arachnid

    Nazareth, Taís M.; Machado, Glauco


    Female investment in large eggs increases the demand for fatty acids, which are allocated for yolk production. Since the biosynthetic pathway leading to fatty acids uses the same precursors used in the formation of polyketides, allocation trade-offs are expected to emerge. Therefore, egg production should constrain the investment in chemical defenses based on polyketides, such as benzoquinones. We tested this hypothesis using the harvestman Acutiosoma longipes, which produces large eggs and releases benzoquinones as chemical defense. We predicted that the amount of secretion released by ovigerous females (OFs) would be smaller than that of non-ovigerous females (NOF). We also conducted a series of bioassays in the field and in the laboratory to test whether egg production renders OFs more vulnerable to predation. OFs produce less secretion than NOFs, which is congruent with the hypothesis that egg production constrains the investment in chemical defenses. Results of the bioassays show that the secretion released by OFs is less effective in deterring potential predators (ants and spiders) than the secretion released by NOFs. In conclusion, females allocate resources to chemical defenses in a way that preserves a primary biological function related to reproduction. However, the trade-off between egg and secretion production makes OFs vulnerable to predators. We suggest that egg production is a critical moment in the life of harvestman females, representing perhaps the highest cost of reproduction in the group. PMID:26331946

  7. First Biosynthetic pathway of 1-hepten-3-one in Iporangaia pustulosa (Opiliones)

    Rocha, Daniele F. O.; Wouters, Felipe C.; Machado, Glauco; Marsaioli, Anita J.


    Arthropods produce a great variety of natural compounds, many of which have unexplored biosynthesis. Among the armored harvestmen (Arachnida: Opiliones) of the suborder Laniatores, the defensive gland exudates contain vinyl ketones and other constituents of supposed polyketide origin. We have studied the biosynthesis of 1-hepten-3-one in the Neotropical harvestman Iporangaia pustulosa by feeding individuals with 13C-labeled precursors, demonstrating its mixed acetate/propionate origin. 13C NMR spectroscopy showed an unusual labeling pattern suggesting different propionate sources for starting and extender units. Our analysis also indicates the presence of methylmalonyl-CoA mutase, converting acetate into propionyl-CoA via succinyl-CoA, together with other C3 unit routes. This is the first biosynthetic study of alkyl vinyl ketones in arthropods. Our results shed light on the origin and diversification of chemical compounds in a major arthropod group.

  8. Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China

    Huang, Diying; Selden, Paul A.; Dunlop, Jason A.


    Harvestmen (Arachnida: Opiliones) are familiar animals in most terrestrial habitats but are rare as fossils, with only a handful of species known from each of the Palaeozoic, Mesozoic, and Cenozoic eras. Fossil harvestmen from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China, are described as Mesobunus martensi gen. et sp. nov. and Daohugopilio sheari gen. et sp. nov.; the two genera differ primarily in the relative length of their legs and details of the pedipalps. Jurassic arachnids are extremely rare and these fossils represent the first Jurassic, and only the fourth Mesozoic, record of Opiliones. These remarkably well-preserved and modern-looking fossils are assigned to the Eupnoi, whereby M. martensi demonstrably belongs in Sclerosomatidae. It thus represents the oldest record of a modern harvestman family and implies a high degree of evolutionary stasis among one of the most widespread and abundant groups of long-legged, round-bodied harvestmen.

  9. Wie viele Arten von Milbenkankern (Opiliones, Cyphophthalmi gibt es in Österreich?

    Raspotnig, Günther


    Full Text Available For the last 60 years, the mite-harvestman Cyphophthalmus duricorius Joseph, 1868, a soil-dwelling sironid, has been considered to be the only representative of the opilionid suborder Cyphophthalmi in Austria. However, novel data from recent collections confirm the presence of at least two further Austrian cyphophthalmid species. (1 Siro cf. crassus Novak & Giribet, 2006 occurs in at least one location in SW Styria near the Slovenian border and hence represents a member of a second genus of Austrian sironids. (2 A further morphologically distinct sironid (“Sironidae gen. et sp. nov.?” – so far undescribed and systematically not placed in detail – was collected in the borderland between Styria and Carinthia. All three species can be found in a small area of a few square-kilometers; although no syntopic occurrence was recorded.

  10. A revised dated phylogeny of the arachnid order Opiliones.

    Sharma, Prashant P; Giribet, Gonzalo


    Dating the Opiliones tree of life has become an important enterprise for this group of arthropods, due to their ancient origins and important biogeographic implications. To incorporate both methodological innovations in molecular dating as well as new systematic discoveries of harvestman diversity, we conducted total evidence dating on a data set uniting morphological and/or molecular sequence data for 47 Opiliones species, including all four well-known Palaeozoic fossils, to test the placement of both fossils and newly discovered lineages in a single analysis. Furthermore, we investigated node dating with a phylogenomic data set of 24,202 amino acid sites for 14 species of Opiliones, sampling all extant suborders. In this way, we approached molecular dating of basal harvestman phylogeny using different data sets and approaches to assess congruence of divergence time estimates. In spite of the markedly different composition of data sets, our results show congruence across all analyses for age estimates of basal nodes that are well constrained with respect to fossil calibrations (e.g., Opiliones, Palpatores). By contrast, derived nodes that lack fossil calibrations (e.g., the suborders Cyphophthalmi, and Laniatores) have large uncertainty intervals in diversification times, particularly in the total evidence dating analysis, reflecting the dearth of calibration points and undersampling of derived lineages. Total evidence dating consistently produced older median ages than node dating for ingroup nodes, due to the nested placement of multiple Palaeozoic fossils. Our analyses support basal diversification of Opiliones in the Ordovician-Devonian period, corroborating the inferred ancient origins of this arthropod order, and underscore the importance of diversity discovery-both paleontological and neontological-in evolutionary inference.

  11. Alarm communication: a new function for the scent-gland secretion in harvestmen (Arachnida: Opiliones)

    Machado, Glauco; Bonato, Vinícius; Oliveira, Paulo


    Most harvestmen are nocturnal, nonacoustical, and nonvisual arthropods. They have a pair of exocrine glands on the cephalothorax that produce defensive volatile secretions. We investigated in the field the possible alarm effect of these secretions in the gregarious harvestman Goniosoma aff. proximum. A cotton swab soaked with the species' own exudate (treatment), or with water (control), was held 1-2 cm from the center of harvestmen aggregations. The results showed that the gland secretion elicits an alarm response in Goniosoma: whereas 73.3% of the aggregations dispersed after being stimulated with the gland exudate, only 3.3% responded to the water control. Respondent groups are larger than non-respondent groups, and the time of reaction to the secretion was inversely related to group size. This is the first demonstration of a chemically-mediated alarm effect in harvestmen. The alarm response in gregarious harvestmen has possibly evolved as a by-product of a primarily defensive reaction in the context of predator avoidance. The discovery of this novel function of scent-gland secretion is meaningful in view of the widespread occurrence of gregarious habit among species of the order Opiliones.

  12. The Opiliones tree of life: shedding light on harvestmen relationships through transcriptomics

    Sharma, Prashant P.; Tourinho, Ana Lúcia


    Opiliones are iconic arachnids with a Palaeozoic origin and a diversity that reflects ancient biogeographic patterns dating back at least to the times of Pangea. Owing to interest in harvestman diversity, evolution and biogeography, their relationships have been thoroughly studied using morphology and PCR-based Sanger approaches to infer their systematic relationships. More recently, two studies utilized transcriptomics-based phylogenomics to explore their basal relationships and diversification, but sampling was limiting for understanding deep evolutionary patterns, as they lacked good taxon representation at the family level. Here, we analysed a set of the 14 existing transcriptomes with 40 additional ones generated for this study, representing approximately 80% of the extant familial diversity in Opiliones. Our phylogenetic analyses, including a set of data matrices with different gene occupancy and evolutionary rates, and using a multitude of methods correcting for a diversity of factors affecting phylogenomic data matrices, provide a robust and stable Opiliones tree of life, where most families and higher taxa are precisely placed. Our dating analyses using alternative calibration points, methods and analytical parameters provide well-resolved old divergences, consistent with ancient regionalization in Pangea in some groups, and Pangean vicariance in others. The integration of state-of-the-art molecular techniques and analyses, together with the broadest taxonomic sampling to date presented in a phylogenomic study of harvestmen, provide new insights into harvestmen interrelationships, as well as an overview of the general biogeographic patterns of this ancient arthropod group. PMID:28228511

  13. Hidden Mediterranean diversity: assessing species taxa by molecular phylogeny within the opilionid family Trogulidae (Arachnida, Opiliones).

    Schönhofer, Axel L; Martens, Jochen


    This is the first comprehensive study to evaluate the relationships between the western palearctic harvestman families Dicranolasmatidae, Trogulidae and Nemastomatidae with focus on the phylogeny and systematics of Trogulidae, using combined sequence data of the nuclear 28S rRNA and the mitochondrial cytochrome b gene. Bayesian analysis and Maximum parsimony do not reliably resolve Dicranolasma as distinct family but place it on a similar phylogenetic level as several lineages of Trogulidae. Nemastomatidae and Trogulidae turned out to be monophyletic, as did genera Anelasmocephalus and Trogulus within the Trogulidae. The genera Calathocratus, Platybessobius and Trogulocratus each appeared para or polyphyletic, respectively and are synonymized with Calathocratus. The monotypic genus Kofiniotis is well supported. We show molecular data to be in general concordance with taxa characterized by morphology. Molecular data are especially useful to calibrate morphological characters for systematic purposes within homogeneous taxa. In the majority of closely related valid species we show the lowest level of genetic distance to be not lower than 5%. By this threshold in terms of traditionally accepted species the estimated number of species turns out to be 1.5-2.4 times higher than previously believed. With respect to European fauna cryptic diversity in Trogulidae is obviously extraordinarily high and hitherto largely underestimated.

  14. Costly learning: preference for familiar food persists despite negative impact on survival.

    Costa, Thaiany M; Hebets, Eileen A; Melo, Diogo; Willemart, Rodrigo H


    Animals often rely on events in their environment that provide information (i.e. experience) to alter their future decision-making in ways that are presumed to be beneficial. Such experience-based learning, however, does not always lead to adaptive decision-making. In this study, we use the omnivorous harvestman Heteromitobates discolor to explore the role of past diet on subsequent food choice and survival. We first tested whether a short-term homogeneous diet (rotten crickets, fresh crickets or dog food) influenced subsequent food choice (rotten cricket versus fresh cricket). We next examine the impact of diet on survival. We found that following experience with a homogeneous cricket diet, adult harvestmen displayed a learned preference for familiar food, regardless of whether it was rotten or fresh crickets; individuals experiencing dog food were equally likely to choose rotten versus fresh crickets. We additionally found that individuals that ate rotten crickets suffered shorter survival than those that ate fresh crickets. Together, our results suggest that the diet an individual experiences can lead to maladaptive food preferences-preferences that ultimately result in reduced longevity. © 2016 The Author(s).

  15. Chromosome complement and meiosis of Holmbergiana weyenberghii (Opiliones: Sclerosomatidae: Gagrellinae from Argentina Complemento cromosómico y meiosis de Holmbergiana weyenberghii (Opiliones: Sclerosomatidae: Gagrellinae de Argentina

    Sergio G. Rodríguez Gil


    Full Text Available The cytogenetical analysis of the harvestman Holmbergiana weyenberghii (Holmberg (Eupnoi, Sclerosomatidae, Gagrellinae from Argentina is reported for the first time. The complement of males is composed of 18 chromosomes. In meiosis there are nine homomorphic bivalents: one large, five medium-sized and three small. The chromosome number of H. weyenberghii is within the range of diploid numbers of the subfamily Gagrellinae Thorell, which shows the lowest chromosome numbers among the sclerosomatids.Se analiza citogenéticamente, por primera vez, una especie de opilión proveniente de Argentina: Holmbergiana weyenberghii (Holmberg (Eupnoi, Sclerosomatidae, Gagrellinae. Los machos tienen un complemento cromosómico compuesto por 18 cromosomas. En meiosis, hay nueve bivalentes homomórficos: uno mayor, cinco medianos y tres menores. El número cromosómico de H. weyenberghii se encuentra dentro del rango de números diploides de los Gagrellinae Thorell; esta subfamilia presenta los números cromosómicos más bajos de Sclerosomatidae.

  16. Costly learning: preference for familiar food persists despite negative impact on survival


    Animals often rely on events in their environment that provide information (i.e. experience) to alter their future decision-making in ways that are presumed to be beneficial. Such experience-based learning, however, does not always lead to adaptive decision-making. In this study, we use the omnivorous harvestman Heteromitobates discolor to explore the role of past diet on subsequent food choice and survival. We first tested whether a short-term homogeneous diet (rotten crickets, fresh crickets or dog food) influenced subsequent food choice (rotten cricket versus fresh cricket). We next examine the impact of diet on survival. We found that following experience with a homogeneous cricket diet, adult harvestmen displayed a learned preference for familiar food, regardless of whether it was rotten or fresh crickets; individuals experiencing dog food were equally likely to choose rotten versus fresh crickets. We additionally found that individuals that ate rotten crickets suffered shorter survival than those that ate fresh crickets. Together, our results suggest that the diet an individual experiences can lead to maladaptive food preferences—preferences that ultimately result in reduced longevity. PMID:27405381

  17. Male dimorphism and alternative reproductive tactics in harvestmen (Arachnida: Opiliones).

    Buzatto, Bruno A; Machado, Glauco


    Strong sexual selection may lead small males or males in poor condition to adopt alternative reproductive tactics (ARTs) as a way to avoid the risk of being completely excluded from the mating pool. ARTs, sometimes accompanying morphological dimorphism among males, are taxonomically widespread, especially common in arthropods. Here we review the current knowledge on ARTs and male dimorphism in a diverse but relatively overlooked group of arachnids, the order Opiliones, popularly known as harvestmen or daddy long-legs. We begin with a summary of harvestman mating systems, followed by a review of the two lines of evidence for the presence of ARTs in the group: (1) morphological data from natural populations and museum collections; and (2) behavioral information from field studies. Despite receiving less attention than spiders, scorpions and insects, our review shows that harvestmen are an exciting group of organisms that are potentially great models for sexual selection studies focused on ARTs. We also suggest that investigating the proximate mechanisms underlying male dimorphism in the order would be especially important. New research on ARTs and male dimorphism will have implications for our understanding of the evolution of mating systems, sperm competition, and polyandry. This article is part of a Special Issue entitled: Neotropical Behaviour. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Opiliones are no longer the same--on suprafamilial groups in harvestmen (Arthropoda: Arachnida).

    Kury, Adriano B


    A review of the names used in the arachnid order Opiliones above superfamily level is presented. Many historical branching patterns of Opiliones (for five terminals), of Laniatores (for six terminals), and of Cyphophthalmi (for six terminals) are extrapolated, compared and graphically displayed. For the first time a historical review is made of the circumscriptions of those names and comparisons are drawn to current usage. Critical clades are used as terminals and represented by the oldest valid generic name of each. Comments are made on the variant usage for 25 suprafamilial names from the literature. Cladistic definitions are provided for these names under relevant hypotheses of phylogeny. It is noted that virtually all important suprafamilial names in Opiliones changed concept over time, and the purpose of this project is to clarify the original usage compared to current, and to add historical perspective. Two options are considered for higher-level nomenclature in Opiliones: (1) a circumscriptional option, sticking to the original inclusion of the names; (2) an inertial option, where no name has priority, and follows recent use in the literature. As there is no priority for names not regulated by ICZN, option 2 prevails, because it entails massive momentum. The following new names are introduced as unranked taxa to define clades under different hypotheses of phylogeny: Tricospilata (= Triaenonychidae + Grassatores), Lomaniatores (Laniatores in the restricted sense used by Loman/Pocock), and Eulaniatores (Laniatores excluding the bizarre Synthetonychiidae). Some of the hypotheses implied by these names are conflicting and mutually exclusive, but the state of knowledge of harvestman taxonomy is quickly changing, and no hypothesis that clearly supersedes the others can be detected.

  19. Paternal care decreases foraging activity and body condition, but does not impose survival costs to caring males in a Neotropical arachnid.

    Gustavo S Requena

    Full Text Available Exclusive paternal care is the rarest form of parental investment in nature and theory predicts that the maintenance of this behavior depends on the balance between costs and benefits to males. Our goal was to assess costs of paternal care in the harvestman Iporangaia pustulosa, for which the benefits of this behavior in terms of egg survival have already been demonstrated. We evaluated energetic costs and mortality risks associated to paternal egg-guarding in the field. We quantified foraging activity of males and estimated how their body condition is influenced by the duration of the caring period. Additionally, we conducted a one-year capture-mark-recapture study and estimated apparent survival probabilities of caring and non-caring males to assess potential survival costs of paternal care. Our results indicate that caring males forage less frequently than non-caring individuals (males and females and that their body condition deteriorates over the course of the caring period. Thus, males willing to guard eggs may provide to females a fitness-enhancing gift of cost-free care of their offspring. Caring males, however, did not show lower survival probabilities when compared to both non-caring males and females. Reduction in mortality risks as a result of remaining stationary, combined with the benefits of improving egg survival, may have played an important and previously unsuspected role favoring the evolution of paternal care. Moreover, males exhibiting paternal care could also provide an honest signal of their quality as offspring defenders, and thus female preference for caring males could be responsible for maintaining the trait.

  20. New species in the Sitalcina sura species group (Opiliones, Laniatores, Phalangodidae), with evidence for a biogeographic link between California desert canyons and Arizona sky islands.

    DiDomenico, Angela; Hedin, Marshal


    The western United States is home to numerous narrowly endemic harvestman taxa (Arachnida, Opiliones), including members of the genus Sitalcina Banks, 1911. Sitalcina is comprised of three species groups, including the monospecific Sitalcina californica and Sitalcina lobata groups, and the Sitalcina sura group with eight described species. All species in the Sitalcina sura group have very small geographic distributions, with group members distributed like disjunct "beads on a string" from Monterey south to southern California and southeast to the sky-island mountain ranges of southern Arizona. Here, molecular phylogenetic and species delimitation analyses were conducted for all described species in the Sitalcina sura group, plus several newly discovered populations. Species trees were reconstructed using multispecies coalescent methods implemented in *BEAST, and species delimitation was accomplished using Bayes Factor Delimitation (BFD). Based on quantitative species delimitation results supported by consideration of morphological characters, two new species (Sitalcina oasiensis sp. n., Sitalcina ubicki sp. n.) are described. We also provide a description of the previously unknown male of Sitalcina borregoensis Briggs, 1968. Molecular phylogenetic evidence strongly supports distinctive desert versus coastal clades, with desert canyon taxa from southern California more closely related to Arizona taxa than to geographically proximate California coastal taxa. We hypothesize that southern ancestry and plate tectonics have played a role in the diversification history of this animal lineage, similar to sclerophyllous plant taxa of the Madro-Tertiary Geoflora. Molecular clock analyses for the Sitalcina sura group are generally consistent with these hypotheses. We also propose that additional Sitalcina species await discovery in the desert canyons of southern California and northern Baja, and the mountains of northwestern mainland Mexico.

  1. North Pyrenean populations of Megabunus diadema (Fabricius, 1779 (Arachnida: Opiliones are characterized by highly male-biased sex ratios

    D’Amico, F.


    Full Text Available Megabunus diadema (Fabricius, 1779 is an Atlantic and European harvestman species characterized by a discontinuous distribution from Scandinavia to the Iberian Peninsula. With very few male individuals ever observed in the field until now, the biological uniqueness of the species lies in its reproduction mode, hitherto regarded as asexual, facultative parthenogenesis. Based on a large sample of 741 sexed individuals, the study indicates a sex ratio much higher than what was formerly known, equal to 65.58% of males. Locally varying from 0 to 100% (median 75.5% of males, the sex ratio depends indeed on the altitude and the phenological cycle: the proportion of males decreases with increasing altitude and increases gradually during the spring to reach a plateau in summer. By describing populations locally dominated by male individuals and providing new information on the spatial and temporal patterns of tertiary sex ratio, we question the currently admitted reproduction mode of the species which could be normally sexual, at least locally, rather than asexual. A distribution map of the species on the northern slope of the Pyrenees is provided for the first time. Our study also complements the distribution for the southern slopes of the Pyrenees and the rest of the Iberian Peninsula published recently by Merino-Sáinz et al. (2013.Megabunus diadema (Fabricius 1779 es una especie de opilión Atlántica y Europea, caracterizada por una distribución discontinua desde Escandinavia a la Península Ibérica. La singularidad biológica de la especie se encuentra en el modo de reproducción, la partenogénesis facultativa, hasta ahora considerada como asexual. De hecho, hasta el momento se han observado muy pocos individuos masculinos en el campo. Los resultados de este estudio muestran, sobre una amplia muestra (741 individuos sexuados, que la proporción de sexo masculino es muy superior a lo conocido hasta ahora (65%. Localmente este porcentaje puede